Which of the Following Is True

Which of the following is true?

A) Additional contributing factors, such as morbid obesity, pregnancy, an enlarged heart, and pulmonary effusion, may involve increase of expansion of the lungs.
B) Residual volume (RV) is the volume of gas that remains in the lungs at the beginning of a maximum expiration.
C) A decrease in vital capacity (VC) may also be seen without primary lung disease or airway obstruction.
D) Functional residual capacity (FRC) is the volume of air remaining in the lungs at the resting expiratory level. It contains the expiratory reserve volume (ERV) and the inspiration capacity (IC) .